Efficiency, products and mechanisms of ethyl acetate oxidative degradation in air non-thermal plasma

Ethyl acetate (EA) is a popular solvent and diluent in many products and one of the most ubiquitous organic pollutants of indoor air. Although EA's ascertained toxicity is classified as low, exposure to its vapors at concentrations 400 ppm causes serious problems in humans. EA is thus a frequent target in testing novel technologies for air purification. We report here an investigation of EA oxidative degradation in air at room temperature and atmospheric pressure induced by corona discharges. Three corona regimes, dc-, dc+ and pulsed +, were tested in the same reactor under various experimental conditions with regard to EA initial concentration (C 0) and the presence of humidity in the system. The EA degradation process was monitored by gas chromatography (GC)-flame ionization detection, GC-mass spectrometry and Fourier transform infrared spectroscopy analysis of the treated gas. These analyses yielded the concentration of residual EA (C) and those of its major products of oxidation (CO2, CO) and revealed a few organic reaction intermediates formed along the oxidation chain. The process energy efficiency was determined as energy constant, k E (kJ-1 l) and as energy yield, EY (g kW-1 h-1). The efficiency depends on the type of corona (pulsed + >dc- >dc+), on the presence of humidity in the air (improvement in the case of dc-, little or no effect for dc+) and on C 0 (k E increases linearly with 1/C 0). CO2 and CO were the major carbon containing products, confirming the strong oxidizing power of air non-thermal plasma. Acetic acid and acetaldehyde were detected in very small amounts as reaction intermediates. The experimental results obtained in this work support the conclusion that different reactive species are involved in the initial step of EA oxidation in the case of dc- and dc+ corona air non-thermal plasma

Design of Nb3Sn Coils for LARP Long Magnets

The LHC Accelerator Research Program (LARP) has a primary goal to develop, assemble, and test full size Nb{sub 3}Sn quadrupole magnet models for a luminosity upgrade of the Large Hadron Collider (LHC). A major milestone in this development is to assemble and test, by the end of 2009, two 4 m-long quadrupole cold masses, which will be the first Nb{sub 3}Sn accelerator magnet models approaching the length of real accelerator magnets. The design is based on the LARP Technological Quadrupoles (TQ), under development at FNAL and LBNL, with gradient higher than 200 T/m and aperture of 90 mm. The mechanical design will be chosen between two designs presently explored for the TQs: traditional collars and Al-shell based design (preloaded by bladders and keys). The fabrication of the first long quadrupole model is expected to start in the last quarter of 2007. Meanwhile the fabrication of 4 m-long racetrack coils started this year at BNL. These coils will be tested in an Al-shell based supporting structure developed at LBNL. Several challenges have to be addressed for the successful fabrication of long Nb{sub 3}Sn coils. This paper presents these challenges with comments and solutions adopted or under study for these magnets. The coil design of these magnets, including conductor and insulation features, and quench protection studies are also presented

Effect of CLIQ on training of HL-LHC quadrupole magnets

The high-luminosity LHC upgrade requires stronger than LHC low-beta quadrupole magnets to reach the luminosity goals of the project. The project is well advanced and HL-LHC quadrupole magnets are currently being commissioned in US Labs (MQXFA magnets) and CERN (MQXFB magnets). Those are the first Nb3Sn magnets to be used in any large particle accelerator. At development stages, many Nb3Sn accelerator sub-scale models showed relatively slow training and MQXFA magnets were projected to have low tens of quenches before reaching operational field. Recently it was shown that dedicated capacitor-based devices can affect Nb3Sn magnet training, and it was suggested that CLIQ, a capacitor-based device intended for quench protection, can do too. The present paper investigates effects on training likely induced by CLIQ, using the base fact that only half the coils in a quadrupole experience upward current modulation at quench because of capacitor discharge. The study encompasses all MQXFA production magnets trained at BNL to date. No other high-statistics data from identical magnets (series) with CLIQ protection exist so far. Implications and opportunities stemming from data analysis are discussed and conclusions drawn.Comment: Accepted versio

Isolation and characterization of CD146+ multipotent mesenchymal stromal cells

Mesenchymal stromal cells (MSCs) represent a bone marrow (BM) population, classically defined by five functional properties: extensive proliferation, ability to differentiate into osteoblasts, chondrocytes, adipocytes, and stromal cells−supporting hematopoiesis. However, research progress in this area has been hampered by lack of suitable markers and standardized procedures for MSC isolation. We have isolated a CD146+ multipotent MSC population from 20 human BM donors displaying the phenotype of self-renewing osteoprogenitors; an extensive 12-week proliferation; and the ability to differentiate in osteoblasts, chondrocytes, adipocytes, and stromal cells supporting hematopoiesis. Furthermore, the CD146+ MSCs secrete a complex combination of growth factors (GFs) controlling hematopoietic stem cells (HSCs) function, while providing a >2-log increase in the long-term culture (LTC) colony output in 8-week LTC over conventional assays. The hematopoietic stromal function exhibited by the MSCs was further characterized by manipulating LTCs with the chemical inhibitors Imatinib or SU-5416, targeting two GF receptors (GFRs), KIT or VEGFR2/1, respectively. Both treatments similarly impaired LTC colony output, indicating key roles for these two GF/GFR interactions to support LTC-initiating cell activity. CD146+ MSCs may thus represent a tool to explore the MSC-HSC cross-talk in an in vitro surrogate model for HSC “niches,” and for regenerative therapy studies. In addition, the MSC microRNA (miRNA) expression profile was analyzed by microarrays in both basic conditions and chondrogenic differentiation. Our analysis revealed that several miRNAs are modulated during chondrogenesis, and many of their putative targets are genes involved in chondrogenic differentiation

mRNA/microRNA gene expression profile in microsatellite unstable colorectal cancer

<p>Abstract</p> <p>Background</p> <p>Colorectal cancer develops through two main genetic instability pathways characterized by distinct pathologic features and clinical outcome.</p> <p>Results</p> <p>We investigated colon cancer samples (23 characterized by microsatellite stability, MSS, and 16 by high microsatellite instability, MSI-H) for genome-wide expression of microRNA (miRNA) and mRNA. Based on combined miRNA and mRNA gene expression, a molecular signature consisting of twenty seven differentially expressed genes, inclusive of 8 miRNAs, could correctly distinguish MSI-H versus MSS colon cancer samples. Among the differentially expressed miRNAs, various members of the oncogenic miR-17-92 family were significantly up-regulated in MSS cancers. The majority of protein coding genes were also up-regulated in MSS cancers. Their functional classification revealed that they were most frequently associated with cell cycle, DNA replication, recombination, repair, gastrointestinal disease and immune response.</p> <p>Conclusion</p> <p>This is the first report that indicates the existence of differences in miRNA expression between MSS versus MSI-H colorectal cancers. In addition, the work suggests that the combination of mRNA/miRNA expression signatures may represent a general approach for improving bio-molecular classification of human cancer.</p